1. Technical Field of the Invention
This invention generally relates to the field of communication systems and, more particularly, to exchanging packets between voice switches over the Public Switch Telephone Network (PSTN).
2. Description of the Background Art
The Public Switch Telephone Network (PSTN) was initially developed to handle analog communications, such as voice communication (calls). For example, when a voice call is made, a signaling path is first established between the calling and called parties via local switches serving the respective parties. The signaling path provides audible indications such as dial tone, ringing or a busy signal indications to alert the calling party of the status of the call. If the called party picks up the phone, a voice path is then established between the calling and called party. Unfortunately, the voice path is “connection oriented,” wherein a 64 kb/s channel (also known as a Digital Signal Level Zero (DS0) Channel), is established on a T1 trunk for the duration of the call. The calling and called parties utilize the same DS0 channel. This is an inefficient use of the bandwidth, since 64 kb/s of silence as well as 64 kb/s information is communicated across the link.
Presently, the communications field is evolving toward a “packet oriented” network. Technologies such as Digital Subscriber Line (DSL), wireless and cable telephony, for example, utilize a packet based system. Packet oriented technologies use different paths to communicate packets allowing packets to arrive out of order. The current methodology of communicating packets over a connection oriented system requires terminating the packets and converting the packets to a different format at the switch. Such processing leads to a large latency time and a deterioration of the signal.